We enter and sometimes exit normal quotations with commas. We set up these quotations with tags that tell the reader that what we are about to say are the words of someone else. Even if you are only listening to the words, and not reading them, you will know that what you are about to hear are quoted words.
Example: Georgie said, "Listen to the folks. They know best."
Example: When he said, "Listen to the folks. They know best," he was telling the truth.
Embedded quotes, on the other hand, are not announced as quotes; they are simply slipped into the flow of your own sentence. They are contained in quotation marks, of course, but they don't receive entry or exit commas and set-up tags.
Example: He can tell me to "listen to the folks" all he wants to, but I'm not gonna do it!
Example: It's up to me if I decide to "listen to the folks."
(Message to the one asking this question: I made up these examples on the spot, so I hope that you find them and my entire explanation helpful.)